Vitamin C is not produced in our body and hence is an essential dietary micronutrient. WHO specifies a certain dose of Vitamin C as recommended daily allowance. But certain conditions require more than usual doses of Vitamin C. Let’s explore!
Functions of vitamin C
Vitamin C is crucial for collagen synthesis in our body. Collagen is the backbone protein of bones, tendons, cartilages, skin, teeth, etc.
Also, Vitamin C is a potent antioxidant that protects the important biomolecules in our cells like proteins, lipids, carbohydrates, and nucleic acids.
More importantly, Vitamin C contributes to our body’s immune system. It facilitates the movement of the immune cells to the site of infection, enhances the killing of microorganisms, and increases antibody levels.
In the brain, vitamin C is involved in the formation of certain neurotransmitters, in the process of neurotransmission and neuromodulation. It is involved in cognition and mood stability.
Furthermore, Vitamin C has an important role in hormonal regulation, generation of metabolic energy, gene transcription and epigenetic regulation.
Vitamin C is stored in the brain, adrenal glands, liver, and lungs.
Deficiency of vitamin C
Scurvy is a disease that occurs when our diet lacks vitamin C for over a month. Poor wound healing, susceptibility to fatal infections, severe bleeding are the classic features. All these occur due to severely impaired immunity and weakened collagen structures.
Mild to moderate deficiency can make you more prone to respiratory tract infections and delay wound healing.
Dosage
While the requirement of Vitamin C for preventing Scurvy is as little as ~ 10 mg per day, our recommended daily requirement is 75 mg for women and 90 for men.
100 to 400 mg per day of Vitamin C saturates the plasma in healthy individuals. This is enough to reduce the risk of chronic diseases.
At the same time, certain conditions require more than usual doses of vitamin C in our daily diet.
Smoking and Vitamin C
Tobacco smoke consists of ~4700 toxic compounds. The smoke deposits these toxic compounds when it passes in and out of the alveoli
Tobacco smoking also increases the risk of bacterial and viral infections. Both active and passive smokers require an additional dose of ~ 35 mg per day to fight against the oxidants.
Post surgery wound healing and vitamin C
In postoperative patients, administration of ~ 500 mg of Vitamin C per day has shown to decrease the wound healing time.
Vitamin C also enhances wound healing by helping in the migration of neutrophils to the wound site. The neutrophils sterilize the wound by releasing reactive oxygen species and antimicrobial proteins.
Once the action is completed, macrophages clear up the neutrophils (a process called phagocytosis) and the wound heals.
When there is a deficiency of Vitamin C, macrophages do not clear the dying neutrophils. The dead cells persist and the wound does not heal.
Old age and Vitamin C
Elderly people (>60 years of age) generally have decreased immune function. Decreased immunosurveillance in ageing is why elders end up with infections often.
If proper care is not given, any infection can progress to sepsis. Vitamin C is one of the factors to prevent sepsis and cancer incidence.
Age-related chronic diseases increase oxidative stress. Due to this, the dietary requirement for antioxidants increases.
Diabetes
It is a fact that diabetes patients are prone to infections and many other morbid diseases.
Elevated blood sugar levels and associated persistent low-grade inflammation result in high-level oxidative stress. This increased utilization depletes vitamin C in the cells. The higher glucose level in the blood also prevents the entry of vitamin C into the cells.
Studies show vitamin C supplements of 1000 mg per day can reduce the risk of infection, control oxidative damage, and may also play a role in controlling high blood sugar levels.
Air pollution
People living in highly polluted cities and working in industries, automobile workshops, construction sites, etc are continuously exposed to toxins.
The body uses up the reserve anti-oxidant defence mechanisms in the airway lining. As a result, the respiratory system loses the oxidant-antioxidant balance and is in a constant state of oxidative stress.
Respiratory infections
Neutrophils are our body’s first line of defence cells. They are the first to enter the sites of infection. During severe infection, neutrophils become paralyzed and are unable to get to the site of infection.
One possible cause for this is the depletion of Vitamin C in our body which occurs during infection. Boosting up vitamin C content in the neutrophils can make them active again.
White blood cells (monocytes, eosinophils) release histamine in response to microorganisms, allergens and stress. It is the chemical responsible for the classic flu symptoms like runny nose and eyes, sneezing, etc.
Vitamin C helps in controlling these symptoms. Studies confirm the fact that vitamin C counteracts histamine (just like the antihistamine pills we pop up).
Athletes
People who undergo rigorous physical training like athletes, military people, professional dancers, wrestlers, etc are likely to suffer from tissue damage and inflammation. The body is under heavy physiological stress.
It is important to maintain adequate vitamin C reserve in the body tissues to combat free radical damage and maintain muscle performance.
Takeaway
More than 1000 mg, as a single dose, decreases the bioavailability by 30%. Not only that, it produces gastrointestinal disturbance and carries the risk of kidney stone formation.
A well-nourished person does not require vitamin C supplements. It is easy to get 100 – 400 mg a day through diet. This amount saturates all the tissues and is 100% biologically available. This also prevents the occurrence of many conditions which require more than usual doses of Vitamin C.
Always check whether you got an adequate dose of Vitamin C every day!
References
- Carr, Anitra C, and Silvia Maggini. “Vitamin C and Immune Function.” Nutrients vol. 9,11 1211. 3 Nov. 2017, doi:10.3390/nu9111211